loadflow.m

It s verry good for you

% Program for Bus Power Injections, Line & Power flows (p.u)...

Y = ybusppg();          % Calling Ybus program..
nbus = length(Y);       % no. of buses...
Vm = pol2rect(V,del);   % Converting polar to rectangular..
Iij = zeros(nbus,nbus);
Sij = zeros(nbus,nbus);

% Line Current Flows..
 for m = 1:nbus
     for n = 1:nbus
         if m ~= n
             Iij(m,n) = -(Vm(m) - Vm(n))*Y(m,n); % Y(m,n) = -y(m,n)..
         end
     end
 end
 Iij = sparse(Iij);
 Iijm = abs(Iij);
 Iija = angle(Iij);

 % Load Flows..
 for m = 1:nbus
     for n = 1:nbus
         if m ~= n
             Sij(m,n) = Vm(m)*conj(Iij(m,n));
         end
     end
 end
 Sij = sparse(Sij);
 Pij = sparse(real(Sij));
 Qij = sparse(imag(Sij));
 
 % Bus Power Injections..
 Si = zeros(nbus,1);
 for i = 1:nbus
     for k = 1:nbus
         Si(i) = Si(i) + conj(Vm(i))* Vm(k)*Y(i,k);
     end
 end
 Pi = real(Si);
 Qi = -imag(Si);